CN104828843B - A kind of method extracting food grade potassium bicarbonate from low concentration K+ alkali liquor waste water system - Google Patents

Abstract

The invention discloses a kind of from low concentration K⁺Alkali liquor waste water system extracts the method for food grade potassium bicarbonate, it is characterised in that: with CO₂As acidulant, at ambient pressure will containing K⁺、Na⁺、SiO₃ ^2-、AlO₂ ^-Alkaline waste water be converted into K-Na-CO₃ ^--HCO₃ ^-Solution system, separates, washs removing Si, Al impurity；By atmospheric evaporation concentration technology, separate and obtain Na₂CO₃；Filtrate is placed in autoclave, adds high pressure CO₂, control to separate Na₂CO₃After filtrate pH value, balance pressure and crystallization time, solution system is become K-Na-HCO₃ ^-System, separates, washs, it is thus achieved that refining KHCO₃, after vacuum drying, namely obtain food stage KHCO₃.The inventive method process conditions are easily manipulated, and test dose easily amplifies, with low cost；And the present invention obtains KHCO₃Product indices reaches GB 25589-2010 food stage KHCO₃Requirements.

Description

A kind of method extracting food grade potassium bicarbonate from low concentration K+ alkali liquor waste water system

Technical field

The present invention relates to a kind of technique extracting food grade potassium bicarbonate, be specifically related to by K⁺Alkali liquor waste water system extracts the method for food grade potassium bicarbonate.

Background technology

Potassium bicarbonate is a kind of important industrial chemicals, is mainly used as production potassium carbonate, potassium acetate, potassium arsenite etc., also for industries such as medicine, food, extinguishing chemicals.Include the potassium salt (K of potassium bicarbonate₂CO₃、KCl、K₂SO₄Deng) it is a kind of strategic materials, the status in national economy is most important.But China can to develop water solublity Potash Resources mineral deposit very few, the 1.06% of the proved reserves Jin Zhan world.At present, the external dependence degree of China's potassium salt is up to 70%.Therefore, from alkaline industrial waste water, extract potassium bicarbonate, the present situation of China's potassium salt shortage can be alleviated to a certain extent.(1. Lin Yao front yard, Li Weijun talk Our Countermeasures from world's potassium salt, potash fertilizer production and consumption situation. China's well mine salt, 1994,2,14-18；2. horse great writing, Feng Wuwei, Miao Shiding, Wang Yingbin, Tian Shuxin, the material phase analysis of a kind of novel Potash mineral resources and the experimentation of extraction potassium carbonate. Chinese science D collects 2005,35 (5), 420-427；3. Seedling generation top, horse great writing, Wang Yingbin, white peak, Qi Hongbin, utilize synthetic zeolite mother solution to produce election class potassium carbonate. mineral products comprehensive utilization 2004,4,3-6；4. Seedling generation top, Wang Yingbin, horse great writing, K in aluminosilicate material₂The mensuration of O content. geoscience 2005,30 (03), 343-346；5. Liu Xiang English, Wang Yingbin, K+, Na+, CO₃ ^2-、HCO₃ ^--H₂The mutual Phase Equilibrium of Quaternary System research of O. uranium geology 2008,24 (2), 123-127；6.Li,J.；Zeng,Y.；Yu,X.；Peng,Y.,SolubilityoftheAqueousReciprocalQuaternarySystemLi⁺,Na⁺//CO₃ ^2-,SO₄ ^2--H₂Oat273.15K.J.Chem.Eng.Data2013,58(2),455-459；7. Zheng's Cortex et Radix Polygalae, Zeng Ying, Lin Xiaofeng, K₂CO₃-Na₂CO₃-H₂O ternary system 273K phase equilibrium experiment research. salt industry and chemical industry 2006,36 (1), 7-9；8. horse great writing, Wang Yingbin, Miao Shiding, Zhang Xiaoyun, Qi Hongbin, Chinese patent, The Chinese Geology Univ. (Beijing), 2003.1.17)

Summary of the invention

It is desirable to provide it is a kind of from low concentration K⁺Alkali liquor waste water system extracts the method for food grade potassium bicarbonate.

This invention address that technical problem, adopt the following technical scheme that

The present invention is from low concentration K⁺Alkali liquor waste water system extracts the method for food grade potassium bicarbonate, and it is characterized in that and comprises the steps:

1st step: take containing K⁺、Na⁺、SiO₃ ^2-And AlO₂ ^-Alkali liquor waste water, K in described alkali liquor waste water⁺Concentration is 200-400mg/L, Na⁺Concentration is 160-800mg/L, SiO₃ ^2-Concentration is 30-50mg/L and AlO₂ ^-Concentration is 15-30mg/L；In described alkali liquor waste water, CO is passed under normal pressure, stirring₂Gas, carries out acidifying to described alkali liquor waste water, when the pH value to described alkali liquor waste water is 7.8-8.2, the white precipitate being made up of Si contamination precipitation and Al contamination precipitation, sucking filtration, washing occurs, discards described white precipitate, it is thus achieved that filtrate A；

2nd step: adopt atmospheric evaporation concentration technology, the density of described filtrate A is concentrated into 1.28g/cm³, then it is down to room temperature at room temperature crystallization 2.0h, white crystal occurs, is the Na containing water of crystallization₂CO₃Crystal；Separate and obtain liquor B and the Na containing water of crystallization₂CO₃Crystal, to the described Na containing water of crystallization₂CO₃Crystal calcining obtains Na₂CO₃；

3rd step: be placed in autoclave by liquor B, adds high pressure CO₂, controlling the pH value of liquor B at 6.5-8.0, balance pressure is 0.2-0.5MPa, and crystallization time is 1.0-3.0h, and liquor B is become K-Na-HCO₃ ^-Solution system, now, at described K-Na-HCO₃ ^-Solution there is crystal settling, i.e. KHCO₃Crystalline hydrate, separates, washs, and namely obtains refining KHCO₃。

4th step: by K-Na-HCO remaining in step 3₃ ^-Solution is 80～100 DEG C of evaporations at ambient pressure further, it is thus achieved that crystal, are also KHCO₃Crystalline hydrate；Isolated by filtration, washing, it is thus achieved that refining KHCO₃And liquor C；

5th step: the refining KHCO that the 3rd step and the 4th step are obtained₃Merge, vacuum drying 6h at 80 DEG C, namely obtain food stage KHCO₃Product.

6th step: the liquor C of the 4th step is reclaimed and puts in the alkali liquor waste water of next round and recycle.

Alkali liquor waste water used by 1st step of said method is electrolysis waste solution or the waste liquid of commercial synthesis zeolite molecular sieve.

The Na obtained in 2nd step of said method₂CO₃Purity > 99.9%, reach analytical pure requirement, it is possible to sell as analytical reagent or use.

Gained food stage KHCO₃Product carries out performance test according to GB25589-2010 standard.Index includes: total alkali content is (with KHCO₃Meter), water insoluble matter content, loss on drying, pH (100g/L solution), heavy metal (in Pb)/(mg/kg) and arsenic (As)/(mg/kg).For containing the impurity such as Si, Al in industrial wastewater, the application gives the Si content of sample (with SiO₂Meter) with Al content (with Al₂O₃Meter).

Beneficial effects of the present invention is embodied in:

Used herein is low concentration K⁺Alkali liquor waste water, through easy steps such as evaporation, crystallization, filtration, washings, can obtain KHCO₃Refined products, process conditions are easily manipulated, and test dose easily amplifies, with low cost；And the present invention obtains KHCO₃Product indices reaches GB25589-2010 food stage KHCO₃Requirements；Material its use, KHCO to the greatest extent in the present invention₃Yield reach more than 90%；In addition the inventive method achieves CO₂Recycling, and easily realize the recovery of purification & isolation liquid and recycle, be a green technology；By control ph, solution density and crystallization time, the method for the present invention can be docked with existing industrial evaporation, crystallization apparatus.

Accompanying drawing explanation

Fig. 1 is the process chart utilizing industrial alkali liquid waste water to produce food grade potassium bicarbonate

Fig. 2 the present invention relates to because of high pressure CO₂Addition, brine system generation phase in version, namely by Na⁺-K⁺-CO₃ ^2--H₂O to Na⁺-K⁺-HCO₃ ^--H₂The brine system of O end-member composition.

Detailed description of the invention

Embodiment 1

1st step, takes alkali liquor waste water 5.0kg, its K⁺Concentration is that 251.6mg/L is (with K₂O counts), Na⁺Concentration 180.0mg/L is (with Na₂O counts), SiO₃ ^2-Concentration 30.5mg/L is (with SiO₂Meter), AlO₂ ^-Concentration at 18.2mg/L (with Al₂O₃Meter).Under an atmospheric pressure (1.0atm, 101.3kPa), through magnetic agitation, pass into CO₂Gaseous acid choline liquid waste water, treats that alkali liquor pH value of waste water reaches 7.8-8.2, the white precipitate being made up of Si contamination precipitation and Al contamination precipitation, sucking filtration, washing occurs, discards white precipitate, it is thus achieved that filtrate A；

2nd step, filtrate A adopts atmospheric evaporation concentration technology, evaporating temperature about 100 DEG C, and filtrate A density is from 1.05g/cm³Fade to 1.28g/cm³, treat the near room temperature of temperature, system is crystallization 2.0h at room temperature, a large amount of white crystal occurs, is the Na containing water of crystallization₂CO₃Crystal；Separate and obtain the Na containing water of crystallization₂CO₃Crystal and liquor B, to the Na containing water of crystallization₂CO₃Crystal is calcined, calcining heat 300 DEG C, time 2.0h, it is thus achieved that Na₂CO₃Product (purity > 99.9%, reach analytical pure requirement)；

3rd step, is placed in autoclave by liquor B, adds high pressure CO₂, controlling the pH value of liquor B 7.0, balance pressure P=0.3MPa, crystallization time is 2.0h, now, at K-Na-HCO₃ ^-Also occurring crystal settling in solution system, analyze result, this crystal is KHCO₃·xH₂O (x=0.5-1.0), separation, cold water washing, namely obtain refining KHCO₃。

4th step, the K-Na-HCO that upper step is obtained₃ ^-Solution is 90 DEG C of evaporations at ambient pressure further, it is thus achieved that crystal is also KHCO₃Crystalline hydrate；Isolated by filtration, cold water wash, and also can obtain KHCO₃Crystal and liquor C.

5th step, the refining KHCO that the 3rd step and the 4th step are obtained₃Merge, vacuum drying 6h at 80 DEG C, it is thus achieved that food stage KHCO₃。

6th step, mixes the cleaning mixture of liquor C with the 3rd step, the 4th step the 5.0kg alkali liquor waste water adding next round, is repeated aforesaid operations technique, circulates five times, calculates product KHCO₃Contrasting with the potassium total amount in 25.0kg raw wastewater alkali liquor, yield is 90.5%.

Embodiment 2

1st step, take the alkali liquor waste water 5.0kg, its K of different batches⁺Concentration is that 280.6mg/L is (with K₂O counts), Na⁺Concentration 178.6mg/L is (with Na₂O counts), SiO₃ ^2-Concentration 35.0mg/L is (with SiO₂Meter), AlO₂ ^-Concentration at 18.0mg/L (with Al₂O₃Meter), under 1.0atm, magnetic agitation process adds and passes into CO₂Gaseous acid choline liquid waste water, treats solution ph about 8.0, white precipitate, sucking filtration, washing occurs, discards white precipitate, it is thus achieved that filtrate A；

2nd step, filtrate A adopt atmospheric evaporation concentration, and filtrate A density is from 1.08g/cm³Fade to 1.28g/cm³, after temperature is down to room temperature, at room temperature crystallization 2.0h, precipitate out white crystal, for the Na containing water of crystallization₂CO₃Crystal；Separate and obtain the Na containing water of crystallization₂CO₃Crystal and liquor B, to the Na containing water of crystallization₂CO₃Crystal calcining obtains Na₂CO₃(purity > 99.9%, reach analytical pure requirement)；

3rd step, liquor B is placed in autoclave, adds high pressure CO₂, controlling the pH value of liquor B about 6.5, balance pressure P=0.5MPa, crystallization time is 3.0h, now, at K-Na-HCO₃ ^-Also occurring crystal settling in solution system, analyze result, this crystal is KHCO₃Crystalline hydrate, separation, cold water washing, namely obtain refining KHCO₃。

4th step, by remaining for upper step K-Na-HCO₃ ^-The lower 90 DEG C of evaporations of solution normal pressure, it is thus achieved that crystal is also KHCO₃Crystalline hydrate.Isolated by filtration, cold water wash, and also can obtain KHCO₃Crystal and liquor C.

5th step, the refining KHCO that the 3rd step and the 4th step are obtained₃Merge, vacuum drying 6h at 80 DEG C, namely obtain food stage KHCO₃。

6th step, mixes the cleaning mixture of liquor C with the 3rd step, the 4th step the 5.0kg alkali liquor waste water adding next round, is repeated aforesaid operations technique, circulates five times, calculates product KHCO₃With the potassium total amount in raw wastewater alkali liquor, yield is 96.0%.

Embodiment 3

1st step, conversion alkali liquor waste water component, its K⁺Concentration is that 380mg/L is (with K₂O counts), Na⁺Concentration 198.5mg/L is (with Na₂O counts), SiO₃ ^2-Concentration 45.8mg/L is (with SiO₂Meter), AlO₂ ^-Concentration at 26.4mg/L (with Al₂O₃Meter).Take 5.0kg alkali liquor waste water, under 1.0atm, under magnetic agitation, pass into CO₂Gaseous acid choline liquid waste water, treats solution ph about 8.0, white precipitate, sucking filtration, washing occurs, discards white precipitate, it is thus achieved that filtrate A；

2nd step, filtrate A adopt atmospheric evaporation concentration, and filtrate A density is from 1.12g/cm³Fade to 1.28g/cm³, after temperature is down to room temperature, at room temperature crystallization 2.0h, precipitate out white crystal, for the Na containing water of crystallization₂CO₃Crystal；Separate and obtain the Na containing water of crystallization₂CO₃Crystal and liquor B, to the Na containing water of crystallization₂CO₃Crystal calcining obtains Na₂CO₃(purity > 99.9%, reach analytical pure requirement)；

3rd step, liquor B is placed in autoclave, adds high pressure CO₂, controlling the pH value of liquor B 6.6, balance pressure P=0.3MPa, crystallization time is 3.0h, now, at K-Na-HCO₃ ^-Also occurring crystal settling in solution system, analyze result, this crystal is KHCO₃Crystalline hydrate, separation, cold water washing, namely obtain refining KHCO₃。

4th step, by remaining for upper step K-Na-HCO₃ ^-The lower 90 DEG C of evaporations of solution normal pressure, it is thus achieved that crystal is also KHCO₃Crystalline hydrate.Isolated by filtration, cold water wash, and also can obtain KHCO₃Crystal and liquor C.

5th step, the refining KHCO that the 3rd step and the 4th step are obtained₃Merge, vacuum drying 6h at 80 DEG C, namely obtain food stage KHCO₃。

6th step, mixes the cleaning mixture of liquor C with the 3rd step, the 4th step the 5.0kg alkali liquor waste water adding next round, is repeated aforesaid operations technique, circulates five times, calculates product KHCO₃With the potassium total amount in raw wastewater alkali liquor, yield is 90.0%.

The KHCO that above-described embodiment is produced₃Testing, and compare with the index of the food grade potassium bicarbonate of GB25589-2010, result is in Table 1.

The contrast table of the potassium bicarbonate product prepared by table 1 embodiment 1,2,3 and GB25589-2010

Additionally, the side-product analytical pure Na that the above embodiment of the present invention is made₂CO₃, its experimental products meets the standard of GB210-92 (Group III, high-class product).

Claims (2)

1. one kind from low concentration K⁺Alkali liquor waste water system extracts the method for food grade potassium bicarbonate, it is characterised in that comprise the steps:

1st step: take containing K⁺、Na⁺、SiO₃ ^2-And AlO₂ ^-Alkali liquor waste water, K in described alkali liquor waste water⁺Concentration is 200-400mg/L, Na⁺Concentration is 160-800mg/L, SiO₃ ^2-Concentration is 30-50mg/L and AlO₂ ^-Concentration is 15-30mg/L；In described alkali liquor waste water, CO is passed under normal pressure, stirring₂Gas, carries out acidifying to described alkali liquor waste water, when the pH value to described alkali liquor waste water is 7.8-8.2, the white precipitate being made up of Si contamination precipitation and Al contamination precipitation, sucking filtration, washing occurs, discards described white precipitate, it is thus achieved that filtrate A；

2nd step: adopt atmospheric evaporation concentration technology, the density of described filtrate A is concentrated into 1.28g/cm³, then it is down to room temperature at room temperature crystallization 2.0h, white crystal occurs, is the Na containing water of crystallization₂CO₃Crystal；Separate and obtain liquor B and the Na containing water of crystallization₂CO₃Crystal, to the described Na containing water of crystallization₂CO₃Crystal calcining obtains Na₂CO₃；The Na obtained₂CO₃Purity > 99.9%, reach analytical pure requirement；

3rd step: be placed in autoclave by liquor B, adds high pressure CO₂, controlling the pH value of liquor B at 6.5-8.0, balance pressure is 0.2-0.5MPa, and crystallization time is 1.0-3.0h, and liquor B is become K-Na-HCO₃ ^-Solution system, now, at described K-Na-HCO₃ ^-Solution there is crystal settling, i.e. KHCO₃Crystalline hydrate, separates, washs, and namely obtains refining KHCO₃。

4th step: by K-Na-HCO remaining in step 3₃ ^-Solution is 80～100 DEG C of evaporations at ambient pressure further, it is thus achieved that crystal, are also KHCO₃Crystalline hydrate；Isolated by filtration, washing, it is thus achieved that refining KHCO₃And liquor C；

5th step: the refining KHCO that the 3rd step and the 4th step are obtained₃Merge, vacuum drying 6h at 80 DEG C, namely obtain food stage KHCO₃Product.

6th step: the liquor C of the 4th step is reclaimed and puts in the alkali liquor waste water of next round and recycle.

2. method according to claim 1, it is characterised in that: alkali liquor waste water used by the 1st step is electrolysis waste solution or the waste liquid of commercial synthesis zeolite molecular sieve.